Track assemblies are complex, and operators generally complain about maintenance issues, as well as the tracks being dislodged or thrown during operation. Further, stair climbing requires a track leading end radius greater than tread height, or requires separate mechanisms. For example, to climb stairs, the surface of the landing preceding the stairs must afford sufficient traction to initiate climbing. Wet, or otherwise slippery, surfaces often thwart climbing.
Wheels are optimal on flat surfaces, and move well over depressions and obstacles, which are less than the radius of the wheel. Wheels have sufficient radius to climb expected and unexpected obstacles and stair heights. However, in surfaces that are loose or covered with snow, the wheels must provide sufficient contact to prevent sinking and must have treads of sufficient texture to maintenance traction. In practice, wheeled robots have not performed well when tested against obstacles such as stairs and rubble.
Whegs assemblies include whegs (wheels) plus leg combinations, which operate nominally as three spokes on a driven axle. On a flat surface, the assembly operates as if legs (i.e., the spokes) are articulating and walking across the surface. Upon reaching an obstacle, the spokes appear to climb up the obstacle as legs would. However, there is a compromise between traction and smoothness of operation. For example, an unwanted up and down, side-to-side jerky displacement can be experienced during locomotion. This jerky operation creates stress on payloads and disrupts video impacting navigation and surveillance.
Thus, a robust ground traction (drive) mechanism for remotely controlled vehicles, which not only operate smoothly on surfaces that are flat, but also upon surfaces that include rugged terrain, snow, mud, and sand, may be beneficial.